Previous investigations have shown injection of nicotine into rats to have acute effects on anterior pituitary gland (APG) hormone release. We now have preliminary data that injection of nicotine into pregnant rats interferes with the development of the two APG cell types we examined, gonadotrophs and somatotrophs. We will examine in detail the acute and chronic effects of nicotine administered during pregnancy and/or lactation, or during young adulthood on the development and maintenance of 6 APG cell types (gonadotrophs (LH or HH/FSH cells), somatotrophs, corticotrophs, lactotrophs, and thyrotrophs), the morphometry of these cells, their secretory ability, and some of the neuropeptides which control their secretions. Techniques to be employed include radioimmunoassay of serum and APG hormones as well as APG hormone released into culture medium from glands in organ culture some of which will be stimulated by neuropeptides, radioimmunoassay of hypothalamic neuropeptides, grafting of pituitary glands beneath the renal capsule, immunocytochemical staining of pituitary tissue for observation at the light microscope level and morphometric analyses of the APG cell types using image analysis. These studies are expected to elucidate some of the mechanisms by which nicotine exerts hormonal imbalances which may retard growth and development during the perinatal period and to determine the extent to which fetal and/or neonatal exposure to nicotine exerts chronic alterations in APG function.